Many felt that Marquez was the winner in at least two, if not all three bouts.

Manny Pacquiao and Juan Manuel Marquez will enter the ring Saturday night at the MGM Grand Casino and Hotel in Las Vegas for the fourth and presumably final time (so says Pacquiao). Their first fight in 2004 ended in a draw and Pacquiao narrowly won the rematches in 2008 and 2011. Many felt that Marquez was the winner in at least two, if not all three bouts.

“This fight is more important than the last three because it’s for my legacy,” Marquez, 39, said this week. The careers of the two fighters are inextricably linked for their prior trilogy and Saturday will be the cherry on top. Others think Marquez might be hungrier in this bout in an attempt to try and show the world that he was the rightful winner of the first three fights. “For Pacquiao, it’s another payday. For Marquez, it’s his legacy,” said boxing trainer and commentator Teddy Atlas on ESPN this week.

Saturday will be another huge payday for Pacquiao, who ranked No. 2 in Forbes most recent look at the world’s highest-paid athletes with earnings of $62 million (only fellow boxer Floyd Mayweather ranked higher). The 16,000-plus seats in the arena are sold out generating a gate of $10.5 million. Pacquiao is guaranteed $8.6 million for the fight, but his share of pay-per-view revenues will push his paycheck past $20 million. Marquez is guaranteed $3 million, but could reach up to $10 million with a big PPV audience.

Their third fight in November 2011 generated 1.3 million PPV buys and Saturday is expected to easily top 1 million buys. It will be Pacquiao’s sixth fight at that level, which would tie the record set by Mike Tyson for most fights with 1 million buys (Mayweather has five fights with 1 million buys). Pacquiao still trails PPV’s Big 3 in all-time buys in Oscar De La Hoya (12.8 million), Evander Holyfield (12.6 million) and Tyson (12.4 million).

Pacquiao’s legacy is secure. He is boxing’s first eight-division world champion and was chosen as the Fighter of the Decade (2000s) by most governing bodies. But what happens if Pacquiao loses? It would be his third straight bad result after the 2011 controversial Marquez win and a June loss to Timothy Bradley, where most viewers thought Pacquiao was robbed. Boxing is in trouble if it loses Pacquiao as a guaranteed PPV superstar. “The market for midsize pay-per-view events has virtually disappeared because of the economy,” says Richard Schaefer, CEO of Golden Boy Promotions. Will Pacquiao continue to generate 1 million PPV buys for his fights and $20+ million paydays for himself with another loss?

Pacquiao and Mayweather are still the two biggest stars in boxing, but Pacquiao will be 34 this month and the end can come quickly for boxers, as detailed in yesterday’s New York Times story “Pacquiao, Like All Boxers, Is in Fight Against Time.” De La Hoya remained a huge PPV draw at the end of his career despite alternating wins and losses for his final seven bouts. Pacquiao, of course, has interests outside of boxing, particularly in politics. He was elected as a Congressman in the Philippines in 2010 and has been bandied about as a presidential candidate when his boxing career is over. Pacquiao and his camp have talked about fighting anywhere from one to three more years.

Before Pacquiao makes a run for president, he has at least one more fight left. The result will help define the legacies of both men in the ring.